The human axilla is populated with two classes of sweat glands: eccrine and apocrine. The eccrine glands produce a watery secretion in response to heat, and the apocrine glands produce microdroplets of a viscous secretion in response to emotional stress. Aprocrine sweat is a complex mixture containing cholesterol, steroids, and other lipids, as well as 10% protein. It is well established that axillary odor is generated from apocrine secretion. Although the sterile fluid is odorless, bacterial action on certain components present in sweat produces the characteristic underarm odor.
It was initially viewed that any or all of the axillary population could cause odor, but it was determined that odor was caused primarily by gram-positive type bacteria. The chemical source of axillary odor has been divided into two classes of odorants: short-chain fatty acids, e.g. isovaleric acid, and the androgen steroids, particularly 5-.alpha.-androstenol and 5-.alpha.-androstenone. ##STR1##
A correlation exits between the composition of the underarm flora and the nature of the odor produced. Where the axillary microbial population is dominated by coryneform bacteria (lipophilic diphtheroids) the acrid odor of delta-16 steroids is apparent, whereas, if the axillary population is dominated by micrococci such as Staphylococcus epidermidis, the odor of isovaleric acid prevails. Pronounced axillary odor is further associated with the presence of the coryneform flora. The prior art has thus identified axillary steroids and have linked their presence with indigenous bacteria, however the mechanism of bacterial action in producing odor has remained uncertain.
In general, steroids are not water-soluble and are normally transported in body fluids as their water-soluble conjugates with sulfate or glucuronic acid. The present invention reveals that the origin of volatile free steroids in the axilla, thought to be responsible for axillary odor, are from the apocrine secretions which contain the steroids as their water-soluble conjugates. Conversion in vivo to the free steroid requires the action of hydrolytic enzymes. It is the production of these enzymes that represents the contribution of bacteria to the generation of underarm odor through the hydrolysis of steroid conjugates, as shown below. The sterile apocrine sweat deposits the water-soluble, odorless steroid conjugates onto hair and skin in the axilla, where enzymes secreted by local bacteria release the volatile, odorous, free steroids. The enzymes which hydrolyze the steroid esters can be any of several bacterial exoesterases--for example, beta-glucuronidase (beta-G) and aryl sulfatase (AS). ##STR2##
The prior art has disclosed various compositions and methods of combating body odors in the formulation of deodorant compositions containing deodorant active agents. As an example, U.S. Pat. No.4,565,693 to Marschner, assigned to the Applicant, discloses a deodorant composition containing zinc glycinate as a non-irritating effective deodorant agent which chemically neutralizes odoriferous compounds and inhibits bacterial growth.
The deodorant compositions in Marschner contain zinc glycinate in anhydrous or hydrated bis (glycino) forms. In Marschner it was originally thought that the deodorant active material possessed the dual function of reducing odor by indirectly inhibiting bacterial growth and chemically neutralizing body odors. Certain ingredients, such as inorganic acids, organic acids or water soluble metal salts of fatty acids were thought to deactivate the deodorant properties of the zinc glycinate deodorant formulations.
The present invention however has further provided a method of directly inhibiting bacterial exoenzymes responsible for the production of steroidal malodor. Deodorant active materials of the invention inhibit the bacterial exoenzymes secreted by local bacteria to prevent release of volatile, odorous, free steroids which are responsible for the axillary malodor. The deodorant active materials including Zn++ compounds, preferably zinc glycinate, function as bacterial exoenzyme inhibitors and are substantive to skin and hair.
Thus present practice to date has not yet provided deodorant compositions or methods of preventing steroidal axillary malodor through direct inhibition of bacterial exoenzymes. There is a need in the art for a method of inhibiting bacterial exoenzymes responsible for the production of steroidal axillary malodor. This invention is directed to the provision of such processes which have wide range applications in creating deodorant compositions. It would be appreciated that advantage over prior art methods of deodorizing would be obtained by providing an effective deodorant composition to prevent the production of steroidal axillary malodor without disturbing the natural flora of the axilla.
Accordingly, it is a broad object of the invention to provide deodorant compositions comprising deodorant active material, which are inhibitors of bacterial exoenzymes responsible for the production of steroidal axillary malodor, dissolved or suspended in a cosmetic vehicle.
A more specific object of the invention is to provide deodorant compositions comprising deodorant active material which inhibit the bacterial exoenzymes aryl sulfatase and beta glucuronidase responsible for the production of steroidal axillary malodor.
Another object of the invention is to provide a method of inhibiting bacterial exoenzymes responsible for the production of steroidal axillary malodor by dissolving or suspending a deodorant active material in a cosmetic vehicle to produce a deodorant composition to prevent the production of axillary odor.
A specific object of the invention is to provide deodorant compositions containing a deodorant active material that inhibits the odor-producing axillary bacterial exoenzymes, which may be in the form of a soap, lotion, fluid, cream, gel stick, powder or spray.